Doctor Who first aired on 23 November 1963, and introduced the world to “the Doctor” a Time Lord who fled his planet (later identified as Gallifrey), to travel through time and space in a machine known as the TARDIS. According to the Doctor’s granddaughter Susan, who claimed that she coined the acronym, TARDIS stands for "Time and Relative Dimension in Space."
This ship resembles the blue British police call boxes that were ubiquitous on the streets of many English cities in the 1960s. It was explained that the TARDIS has a “chameleon circuit” that allows it to take on the image of something common to the surroundings of the planet that it lands on, but the circuit broke after a trip to 1960s London and the TARDIS is now stuck in this form until the Doctor gets around to fixing it.
The chameleon circuit is but one of those TARDIS tidbits that lifelong fans debate and new viewers often get wrong when they discuss the show. With several decades of writers and showrunners, story points are changed, established lore is contradicted, or some things are simply just forgotten, even by the most dedicated fans.
10. The Round Things Don't Have A Function
The “round things” (as the Tenth and Eleventh Doctors affectionately call them) are called roundels, and are circular or hexagonal design elements within the walls of the TARDIS control room.
It's often forgotten that these roundels are more than just decorative, and that they've had many different functions over the decades.
The roundels have been used to access the TARDIS' interior circuitry, to hold lights, and the Third Doctor even used one of them as a scanner. The First Doctor kept brandy within one of the roundels, and River Song had an entire mini bar tucked away inside one. “Don’t tell Dad!"
By the time of the Tenth Doctor, both he and his next incarnation had forgotten the uses for the roundels, but expressed love for them when they saw them in the War Doctor’s TARDIS.
The Twelfth Doctor lamented the lack of round things in his control room, wondering if he had misplaced them - but he made sure to correct this problem later on!